A large flat panel display has been widely used for an advertisement, as well as a home TV, according to development of a technology thereof, and has been gradually extended to a field of an outdoor display. When a transmissive display such as a TFT-LCD or a self-emissive display such as an active matrix organic light emitting diode (AMOLED) is used as a display for outdoor in the bright sunny daytime, it is not easy to represent luminance in itself for maintaining appropriate visibility, and even though it is possible, there is a serious problem in that power consumption increases due to high luminance and thus life is shortened. A reflective display configured to perform a display by using external light may be a realistic alternative, but has a disadvantage in that the reflective display cannot be used when the external light is weak.
Accordingly, a display having a function of a transmissive/self-emissive device and a function of a reflective device has been developed so as to use a display day and night, and a representative example thereof is a transflective LCD.
FIG. 1 is the most representative transflective LCD having a structure in which a transmissive display and a reflective display horizontally occupy one pixel half and half. Since a backlight of the transflective LCD is basically turned on all the time, it is not helpful in reducing energy and also an image quality is not excellent, so that the transflective LCD was eventually failed to be commercialized.
In order to solve a problem regarding energy saving and achieve excellent image quality regardless of a degree of peripheral brightness, a display capable of freely switching a reflective mode and an emissive mode needs to be implemented.
In the meantime, the AMOLED has been developed to enter a large TV market following the success of the mass production of a small and medium mobile display, and the AMOLED has noticeably more potential as a core display mode of a next generation transparent flexible display. Accordingly, there is a high possibility that a dual mode display, which uses the AMOLED or a self-emissive device such as an LED and a QD when a place is indoor or sun light is weak, and switches to a reflective mode in an outdoor place having strong sun light, will have competitive marketability in the medium to longer term.